Display device including a conductive line disposed on an insulating layer groove and a method of manufacturing the same

ABSTRACT

A display device is provided including a first conductive line disposed on a substrate. A first insulating layer is disposed on the substrate at least partially covering the first conductive line. The first insulating layer has a contact hole, which exposes the first conductive line, and a groove recessed in a direction towards the substrate. The groove has a depth smaller than a depth of the contact hole. A second conductive line is disposed in the groove on the first insulating layer and is connected to the first conductive line through the contact hole.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. § 119 to Korean PatentApplication No. 10-201941114754, filed on Sep. 18, 2019 in the KoreanIntellectual Property Office (KIPO), the disclosure of which isincorporated by reference herein in its entirety.

TECHNICAL FIELD

Exemplary Embodiments of the present invention relate to a displaydevice, and more particularly, a display device including a conductiveline disposed on an insulating layer groove and a method ofmanufacturing the same.

Discussion of the Related Art

An organic light emitting diode display device is a self-emissiondisplay device for displaying an image by using an organic lightemitting diode (OLED) that emits light. Such an organic light emittingdiode display device has high quality characteristics such as low powerconsumption, high luminance, and a high response speed. Therefore, theorganic light emitting diode display device is spotlighted as anext-generation display device. The organic light emitting diode mayinclude a pixel electrode, a light emitting layer, and a counterelectrode which are sequentially disposed on a substrate.

A conductive line for transmitting a signal, a voltage, and the like maybe disposed under the organic light emitting diode. A protrusion may beformed on a portion of the pixel electrode that is at least partiallyoverlapped by the conductive line due to a step difference caused by theconductive line. In such a case when the pixel electrode is not flat,the protrusion of the pixel electrode may be visible when the organiclight emitting diode display device does not display the image, andcolor deviation may occur depending on a viewing direction when theorganic light emitting diode display device displays the image.

SUMMARY

According to an exemplary embodiment of the present invention, a displaydevice is provided including a first conductive line disposed on asubstrate. A first insulating layer is disposed on the substrate atleast partially covering the first conductive line. The first insulatinglayer has a contact hole, which exposes the first conductive line, and agroove recessed in a direction towards the substrate. The groove has adepth smaller than a depth of the contact hole. A second conductive lineis disposed in the groove on the first insulating layer and is connectedto the first conductive line through the contact hole.

According to an exemplary embodiment of the present invention, a secondinsulating layer is disposed on the first insulating layer at leastpartially covering the second conductive line, and the groove has around shape recessed in the direction towards the substrate.

According to an exemplary embodiment of the present invention, thesecond conductive line has a ‘U’ shape.

According to an exemplary embodiment of the present invention, thegroove has a rectangular shape recessed in the direction towards thesubstrate.

According to an exemplary embodiment of the present invention, thesecond conductive line has a flat top surface.

According to an exemplary embodiment of the present invention, a maximumdepth of the groove is substantially equal to a thickness of the secondconductive line.

According to an exemplary embodiment of the present invention, the firstconductive line extends in a first direction and is configured totransmit a data signal.

According to an exemplary embodiment of the present invention, thesecond conductive line extends in the first direction and a seconddirection intersecting the first direction. The second conductive lineconnects a pad to the first conductive line.

According to an exemplary embodiment of the present invention, the firstinsulating layer includes an organic insulating material and aninorganic insulating material.

According to an exemplary embodiment of the present invention, thesecond insulating layer includes an organic insulating material.

According to an exemplary embodiment of the present invention, a pixelelectrode is disposed on the second insulating layer at least partiallyoverlapping the second conductive line. A light emitting layer isdisposed on the pixel electrode, and a counter electrode is disposed onthe light emitting layer.

According to an exemplary embodiment of the present invention, the pixelelectrode is a reflective electrode, and the counter electrode is atransmissive electrode.

According to an exemplary embodiment of the present invention, a methodof manufacturing a display device is provided including forming a firstconductive line on a substrate. A first insulating layer is formed atleast partially covering the first conductive line. A contact hole isformed exposing the first conductive line in the first insulating layerby using a halftone mask. A groove is formed in the first insulatinglayer by using the halftone mask. The groove is recessed in a directiontowards the substrate and has a depth smaller than a depth of thecontact hole. A second conductive line is formed at least partiallyfilling the contact hole and the groove.

According to an exemplary embodiment of the present invention, a secondinsulating layer is formed at least partially covering the secondconductive line. The first insulating layer includes an organicinsulating material.

According to an exemplary embodiment of the present invention, thegroove is formed by isotropically etching the first insulating layer.

According to an exemplary embodiment of the present invention, thegroove has a round shape recessed in the direction towards thesubstrate.

According to an exemplary embodiment of the present invention, a methodof manufacturing a display device is provided including forming a firstconductive line on a substrate. A first insulating layer is formed atleast partially covering the first conductive line. A contact hole isformed exposing the first conductive line in the first insulating layerby using a first mask. A groove is formed in the first insulating layerby using a second mask. The groove is recessed in a direction towardsthe substrate and has a depth smaller than a depth of the contact hole.A second conductive line is formed at least partially filling thecontact hole and the groove. A second insulating layer is formed atleast partially covering the second conductive line.

According to an exemplary embodiment of the present invention, the firstinsulating layer includes an organic insulating material and aninorganic insulating material.

According to an exemplary embodiment of the present invention, thegroove is formed by anisotropically etching the first insulating layer.

According to an exemplary embodiment of the present invention, thegroove has a rectangular shape recessed in the direction towards thesubstrate.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention will be more clearlyunderstood from the following Detailed Description taken in conjunctionwith the accompanying drawings, in which:

FIG. 1 is a plan view illustrating a display device, according to anexemplary embodiment of the present invention;

FIG. 2 is a plan view illustrating first conductive lines included inthe display device of FIG. 1, according to an exemplary embodiment ofthe present invention;

FIG. 3 is a plan view illustrating second conductive lines included inthe display device of FIG. 1, according to an exemplary embodiment ofthe present invention;

FIG. 4 is a plan view illustrating an enlarged region A of FIG. 3including the second conductive lines, according to an exemplaryembodiment of the present invention;

FIG. 5 is a plan view illustrating pixel electrodes included in thedisplay device of FIG. 1, according to an exemplary embodiment of thepresent invention;

FIG. 6 is a cross-sectional view illustrating a cross-section of thedisplay device taken along line I-I′ of FIG. 1, according to anexemplary embodiment of the present invention;

FIG. 7 is a cross-sectional view illustrating a cross-section of thedisplay device taken along line II-II′ of FIG. 1, according to anexemplary embodiment of the present invention;

FIGS. 8, 9, 10, and 11 are cross-sectional views illustrating steps in amethod of manufacturing the display device of FIG. 7, according to anexemplary embodiment of the present invention;

FIG. 12 is a cross-sectional view illustrating a cross-section of thedisplay device taken along line II-II′ of FIG. 1, according to anexemplary embodiment of the present invention; and

FIGS. 13, 14, 15, 16, and 17 are cross-sectional views illustratingsteps in a method of manufacturing the display device of FIG. 12,according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Hereinafter, the present invention will be described more fully withreference to the accompanying drawings in which exemplary embodiments ofthe present invention are shown.

FIG. 1 is a plan view illustrating a display device, according to anexemplary embodiment of the present invention.

Referring to FIG. 1, a display device according to an exemplaryembodiment of the present invention may include a display panel DP and aflexible printed circuit board FPCB. The display panel DP may include adisplay area DA and a peripheral area PA.

A plurality of pixels PX may be disposed in the display area DA. Thepixels PX may be arranged in a matrix form along a first direction e.g.,a DR1 direction) and a second direction (e.g., a DR2 direction)intersecting the first direction (e.g., the DR1 direction).

The peripheral area PA may be disposed on at least one side of thedisplay area DA. For example, the peripheral area PA may extend in thefirst direction (e.g., the DR1 direction) from a side of the displayarea DA. A pad part PP may be disposed in the peripheral area PA. Thepad part PP may be located at a center of the peripheral area PA in thesecond direction (e.g., the DR2 direction). For example, the pad part PPmay have opposite, parallel short sides disposed at equidistantdistances in the second direction (e.g., the DR2 direction) fromrespective short sides of the peripheral area PA that extend in thefirst direction (e.g., the DR1 direction). For example, the pad part PPmight not be located at a periphery of the peripheral area PA in thesecond direction (e.g., the DR2 direction). A plurality of pads may bedisposed in the pad part PP. The flexible printed circuit board FPCB maybe connected to the pad part PP, and signals may be provided to the padsfrom an external device through the flexible printed circuit board.FPCB.

FIG. 2 is a plan view illustrating first conductive lines included inthe display device of FIG. 1, according to an exemplary embodiment ofthe present invention.

Referring to FIGS. 1 and 2, a plurality of first conductive lines 110may be disposed on a substrate 100. The first conductive lines 110 maytransmit data signals to the pixels PX. The first conductive lines 110may extend in the first direction (e.g., the DR1 direction), and may bearranged along the second direction (e.g., the DR2 direction). The firstconductive lines 110 may be respectively connected to pixel columnswhich are arranged along the second direction (e.g., the DR2 direction).

Some of the first conductive lines 110 a located at a center of thedisplay area DA in the second direction (e.g., the DR2 direction) amongthe first conductive lines 110 may be connected to first pads PD1. Thefirst pads PD1 may be connected to the flexible printed circuit boardFPCB, and the data signals may be applied to the first pads PD1 from theflexible printed circuit board FPCB. The first pads PD1 may be disposedon the same layer as the first conductive lines 110, or the first padsPD1 and the first conductive lines 110 may be disposed on differentlayers from one another.

FIG. 3 is a plan view illustrating second conductive lines included inthe display device of FIG. 1, according to an exemplary embodiment ofthe present invention.

Referring to FIGS. 1, 2, and 3, a first insulating layer 120, which atleast partially covers the first conductive lines 110, may be disposedon the substrate 100. A plurality of second conductive lines 130 may bedisposed on the first insulating layer 120. The second conductive lines130 may connect at least one of the first conductive lines 110 b, whichare located at edge portions of the display area DA in the seconddirection (e.g., the DR2 direction) among the first conductive lines110, to second pads PD2. The second pads PD2 may at least partiallyoverlap the first pads PD1 in a thickness direction e.g., a directionperpendicular to an upper surface of the substrate 100). The second padsPD2 may be connected to the flexible printed circuit board FPCB, and thedata signals may be applied to the second pads PD2 from the flexibleprinted circuit board FPCB. The second pads PD2 may be disposed on thesame layer as the second conductive lines 130, or the second pads PD2and the second conductive lines 130 may be disposed on different layersfrom one another.

At least one of the second conductive lines 130 disposed adjacent to theperipheral area PA may extend in at least two directions. The secondconductive lines 130 disposed adjacent to the peripheral area PA mayconnect at least one of the first conductive lines 110 b, which arelocated at the periphery of edge portions of the display area DA spacedin the second direction (e.g., the DR2 direction), to the second padsPD2. In an exemplary embodiment of the present invention, the secondconductive lines 130 may extend in the first direction (e.g., the DR1direction) and the second direction (e.g., the DR2 direction).

Contact holes CH1 may be formed in the first insulating layer 120. Forexample, the contact holes CH1 may be formed at a periphery of edgeportions of the display area DA spaced apart in the second direction(e.g., the DR2 direction) and may connect to the first conductive lines110 b. The second conductive lines 130 and end portions of some of thefirst conductive lines 110 b, which are located at the periphery of edgeportions of the display area DA spaced in the second direction (e.g.,the DR2 direction), may be connected to each other through the contactholes CH1.

FIG. 4 is a plan view illustrating region A of FIG. 3 including the thesecond conductive lines 130, according to an exemplary embodiment of thepresent invention.

Referring to FIG. 4, the second conductive lines 130 may include firstextension parts EX1 and second extension parts EX2. Each of the firstextension parts EX1 may extend in the first direction (e.g., the DR1direction), and the first extension parts EX1 may be arranged along thesecond direction (e.g., the DR2 direction). Each of the second extensionparts EX2 may extend in the second direction (e.g., the DR2 direction),and the second extension parts EX2 may be arranged along the firstdirection (e.g., the DR1 direction). The first extension part EX1 andthe second extension part EX2 that intersect each other may form a crossshape.

The first extension parts EX1 adjacent to each other in the firstdirection (e.g., the DR1 direction) may be connected to each other toform a vertical wire extending in the first direction (e.g., the DR1direction), and the second extension pans EX2 adjacent to each other inthe second direction (e.g., the DR2 direction) may be connected to eachother to form a horizontal wire extending in the second direction (e.g.,the DR2 direction). The vertical wire and the horizontal wire may beconnected to each other to form the second conductive line 130.

The first extension part EX1 and the second extension part EX2 thatintersect each other to form a cross shape are uniformly arranged alongthe first direction (e.g., the DR1 direction) and the second direction(e.g., the DR2 direction) so that, in a case in which the display devicedoes not display an image, visibility of the display device may beprevented from being decreased, or the decrease of the visibility of thedisplay device may be minimized, even if the second conductive line 130is visible.

FIG. 5 is a plan view illustrating pixel electrodes included in thedisplay device of FIG. 1, according to an exemplary embodiment of thepresent invention.

According to an exemplary embodiment of the present invention, adjacentcolumns of pixels PX might not have the same size.

Referring to FIGS. 1, 3, and 5, a second insulating layer 140 which atleast partially covers the second conductive lines 130 may be disposedon the first insulating layer 120, and a plurality of pixel electrodes150 may be disposed in the display area DA on the second insulatinglayer 140. The pixel electrodes 150 may be arranged substantially in amatrix form along the first direction (e.g., the DR1 direction) and thesecond direction (e.g., the DR2 direction). The pixels PX may be definedin an area in which the pixel electrodes 150 are disposed in the displayarea DA.

FIG. 6 is a cross-sectional view illustrating the display device takenalong line I-I′ of FIG. 1, according to an exemplary embodiment of thepresent invention. Line I-I′ of FIG. 1 might not intersect the firstconductive line 110 and the second conductive line 130.

A buffer layer 101 may be disposed on the substrate 100. The substrate100 may be an insulating substrate including glass, quartz and/orplastic.

The buffer layer 101 may prevent impurities such as oxygen and moisturefrom being diffused to an upper portion of the substrate 100. Inaddition, the buffer layer 101 may provide a flat top surface on theupper portion of the substrate 100. The buffer layer 101 may include aninorganic insulating material such as silicon oxide, silicon nitride,and/or silicon oxynitride. In an exemplary embodiment of the presentinvention, the buffer layer 101 might not be provided.

An active layer 102 may be disposed on the buffer layer 101. The activelayer 102 may be entirely overlapped by the pixel electrode 150 and maybe narrower than the pixel electrode. The active layer 102 may be formedof amorphous silicon, polycrystalline silicon and/or an oxidesemiconductor. The active layer 102 may include a source, region, adrain region, and a channel region disposed between the source regionand the drain region. The source region and the drain region may bedoped with P-type or N-type impurities.

A gate insulating layer 103 which at least partially covers the activelayer 102 may be disposed on the buffer layer 101. The gate insulatinglayer 103 may insulate a gate electrode 104 b disposed on the activelayer 102 from the active layer 102. The gate insulating layer 103 mayinclude an inorganic insulating material such as silicon oxide, siliconnitride and/or silicon oxynitride.

A gate line 104 a and the gate electrode 104 b may be disposed on thegate insulating layer 103. The active layer 102 may at least partiallyoverlap the gate line 104 a. The gate line 104 a may extend in thesecond direction the DR2 direction) intersecting the first conductiveline 110. The gate line 104 a may transmit a gate signal to the pixelPX. The gate electrode 104 b may at least partially overlap the channelregion of the active layer 102. The gate line 104 a and the gateelectrode 104 b may include a conductive material such as molybdenum(Mo) and/or copper (Cu). The active layer 102, which includes the sourceregion, the drain region, and the channel region, and the gate electrode104 b may form a transistor TR.

A first interlayer insulating layer 105 which at least partially coversthe gate line 104 a and the gate electrode 104 b may be disposed on thegate insulating layer 103. The first interlayer insulating layer 105 mayinsulate a capacitor electrode 106 disposed on the gate electrode 104 bfrom the gate electrode 104 b. In an exemplary embodiment of the presentinvention, the first interlayer insulating layer 105 may include aninorganic insulating material such as silicon oxide, silicon, nitrideand/or silicon oxynitride.

The capacitor electrode 106 may he disposed on the first interlayerinsulating layer 105. The capacitor electrode 106 may at least partiallyoverlap the gate electrode 104 b. The capacitor electrode 106 and thegate electrode 104 b may be substantially a same width. The capacitorelectrode 106 may include a conductive material such as molybdenum (Mo)and/or copper (Cu). The gate electrode 104 b and the capacitor electrode106 may form a capacitor CAP. The capacitor CAP may be disposed betweenthe source electrode 108 a and the drain electrode 108 b.

A second interlayer insulating layer 107 which at least partially coversthe capacitor electrode 106 may be disposed on the first interlayerinsulating layer 105. The second interlayer insulating layer 107 mayinsulate a source electrode 108 a and a drain electrode 108 b disposedon the capacitor electrode 106 from the capacitor electrode 106. In anexemplary embodiment of the present invention, the second interlayerinsulating layer 107 may include an inorganic insulating material suchas silicon oxide, silicon nitride and/or silicon oxynitride.

The source electrode 108 a and the drain electrode 108 b may be disposedon the second interlayer insulating layer 107. The source electrode 108a and the drain electrode 108 b may be connected to the source regionand the drain region of the active layer 102, respectively. For example,the source electrode 108 a and the drain electrode 108 b mayrespectively make contact with the source region and the drain region ofthe active layer 102 through contact holes formed in the gate insulatinglayer 103, the first interlayer insulating layer 105, and the secondinterlayer insulating layer 107. The source electrode 108 a and thedrain electrode 108 b may include a conductive material such as aluminum(Al), titanium (Ti) and/or copper (Cu).

The first insulating layer 120 which at least partially covers thesource electrode 108 a and the drain electrode 108 b may be disposed onthe second interlayer insulating layer 107.

A connection electrode 109 may be disposed on the first insulating layer120. The connection electrode 109 may be connected to the drainelectrode 108 b. For example, the connection electrode 109 may makecontact with the drain electrode 108 b through the contact hole formedin the first insulating layer 120. The connection electrode 109 mayinclude a conductive material such as aluminum (Al), titanium (Ti)and/or copper (Cu).

the second insulating layer 140 which at least partially covers theconnection electrode 109 may be disposed on the first insulating layer120.

A pixel electrode 150 may be disposed on the second insulating layer140. The pixel electrode 150 may be connected to the connectionelectrode 109. For example, the pixel electrode 150 may make contactwith the connection electrode 109 through a contact hole formed in thesecond insulating layer 140.

A pixel defining layer PDL which at least partially covers the pixelelectrode 150 may be disposed on the second insulating layer 140. Thepixel defining layer PDL may have a pixel opening that exposes at leasta portion of the pixel electrode 150. In an exemplary embodiment of thepresent invention, the pixel opening may expose a central portion of thepixel electrode 150, and the pixel defining layer PDL may at leastpartially cover a peripheral portion of the pixel electrode 150. Thepixel defining layer PDL may include an organic insulating material suchas polyimide (PI).

A light emitting layer 160 may be disposed on the pixel electrode 150.The light emitting layer 160 may be disposed on the pixel electrode 150which is exposed by the pixel opening. The light emitting layer 160 mayinclude at least one of an organic light emitting material and a quantumdot.

In an exemplary embodiment of the present invention, the organic lightemitting material may include a low-molecular-weight organic compoundand/or a high-molecular-weight organic compound. For example, thelow-molecular-weight organic compound may include copper phthalocyanine,N,N′-diphenylbenzidine and/or tris-(8-hydroxyquinoline) aluminum, andthe high-molecular-weight organic compound may includepoly(3,4-ethylenedioxythiophene), polyaniline, poly-phenylenevinyleneand/or polyfluorene.

In an exemplary embodiment of the present invention, the quantum dot mayinclude a core including a Group II-VI compound, a Group III-V compound,a Group IV-VI compound, a Group IV element, a Group IV compound, andcombinations thereof. In an exemplary embodiment of the presentinvention, the quantum dot may have a core-shell structure including acore and a shell surrounding the core. The shell may serve as aprotective layer for preventing the core from being chemically denaturedto maintain semiconductor characteristics, and may serve as a charginglayer for imparting electrophoretic characteristics to the quantum dot.

A counter electrode 170 may be disposed on the light emitting layer 160.In an exemplary embodiment of the present invention, the counterelectrode 170 may also be disposed on the pixel defining layer PDL andthe pixel opening. The pixel electrode 150, the light emitting layer160, and the counter electrode 170 may collectively form a lightemitting element EL.

FIG. 7 is a cross-sectional view illustrating a display device takenalong line II-II′ of FIG. 1, according to an exemplary embodiment of thepresent invention. Line II-II′ of FIG. 1 may intersect the firstconductive line 110 and the second conductive line 130.

Referring to FIGS. 6 and 7, the first conductive line 110 may bedisposed on the second interlayer insulating layer 107. The firstconductive line 110 may be disposed on substantially the same level(e.g., a same layer) as the source electrode 108 a and the drainelectrode 108 b, and may include substantially the same material as thesource electrode 108 a and the chain electrode 108 b.

The first insulating layer 120 which at least partially covers the firstconductive line 110 may be disposed on the second interlayer insulatinglayer 107. In an exemplary embodiment of the present invention, thefirst insulating layer 120 may include an organic insulating material.For example, the first insulating layer 120 may include a photosensitivematerial such as a photoresist.

The first insulating layer 120 may have a contact hole CH1 and a grooveGR1. The contact hole CH1 may expose the first conductive line 110. Forexample, the contact hole CH1 may expose a portion of a top surface ofthe first conductive line 110. In this case, the contact hole CH1 mayhave a depth D11 corresponding to a distance from the top surface of thefirst conductive line 110 to a top surface of the first insulating layer120.

The groove GR1 may be recessed in a direction towards the substrate 100,and may have a depth smaller than the depth D11 of the contact hole CH1.For example, lateral surfaces of the groove GR1 may be sloped towards alowermost point of the groove GR1. The top surface of the firstinsulating layer 120 may be recessed in the direction towards thesubstrate 100 by the groove GR1 when viewed in a cross-sectional view.For example, the top surface of the first insulating layer 120 may havea semi-circular recess (e.g., concave), but the present invention is notlimited thereto.

In an exemplary embodiment of the present invention, the groove GR1 mayhave a round shape recessed in the direction towards the substrate 100.The depth of the groove GR1 may be gradually increased from a peripheryto a central portion of the groove GR1. In this case, the groove GR1 mayhave a maximum depth D12 at the central portion.

The second conductive line 130 may be disposed in the groove GR1 on thefirst insulating layer 120. The second conductive line 130 may beconnected to the first conductive line 110 through the contact hole CH1.Accordingly, the data signal may be transmitted from the secondconductive line 130 to the first conductive line 110.

The second conductive line 130 may have a shape that corresponds to ashape of the groove GR1. For example, the second conductive line 130 mayhave a ‘U’ shape when viewed in a cross-sectional view. In a plan view,the groove GR1 and the second conductive line 130 may have a capsuleshape. The second conductive line 130 may be disposed in the groove GR1on the first insulating layer 120, and the second conductive line 130may be formed along a profile of the groove GR1. Accordingly, the secondconductive line 130 may have an upright ‘U’ shape bent in the directiontowards the substrate 100 along the profile of the groove GR1 which hasa round shape recessed in the direction towards the substrate 100.However, the present invention is not limited thereto. For example, thegroove GR1 may have an upside down ‘U’ shape in which downturned sidesextend towards the substrate, and the second conductive line 130disposed therein may have a corresponding shape.

In an exemplary embodiment of the present invention, the maximum depthD12 of the groove GR may be substantially equal to a thickness of thesecond conductive line 130. In this case, a height of a center of a topsurface of the second conductive line 130 may be substantially equal toa height of the top surface of the first insulating layer 120.

The second insulating layer 140 which at least partially covers thesecond conductive line 130 may be disposed on the first insulating layer120. The second insulating layer 140 may include an organic insulatingmaterial. For example, the second insulating layer 140 may includepolyimide (PI) and the like.

A top surface of the second insulating layer 140 may be formed alongprofiles of the top surfaces of the first insulating layer 120 and thesecond conductive line 130 which are disposed under the secondinsulating layer 140. The second conductive line 130 is disposed in thegroove GR1 of the first insulating layer 120 that is recessed in thedirection towards the substrate 100, so that a thickness D13 of a firstprotrusion formed on the top surface of the second insulating layer 140may be smaller than the thickness of the second conductive line 130. Forexample, the first protrusions at least partially overlapping upturnedsides of the second conductive line 130 may have a maximum height fromthe upper surface of the second insulating layer 140 of thickness D13.Thickness D13 may be substantially equal to a difference between amaximum height of an upturned side of the second conductive line 130 andan upper surface of the first insulating layer 120.

The pixel electrode 150 may be disposed on the second insulating layer140. The pixel electrode 150 may at least partially overlap the secondconductive line 130.

A top surface of the pixel electrode 150 may be formed along a profileof the top surface of the second insulating layer 140, which is disposedunder the pixel electrode 150. A second protrusion corresponding to thefirst protrusion formed on the top surface of the second insulatinglayer 140 may be formed on the top surface of the pixel electrode 150.

The light emitting layer 160 may be disposed on the pixel electrode 150,and the counter electrode 170 may be disposed on the light emittinglayer 160. For example, the light emitting layer 160 may have acomplimentary shape to a profile of the pixel electrode 150 includingthe first protrusions.

In an exemplary embodiment of the present invention, the pixel electrode150 may be a reflective electrode, and the counter electrode 170 may bea transmissive electrode. For example, the pixel electrode 150 may beformed of a metal such as magnesium (Mg), silver (Ag), gold (Au),calcium (Ca), lithium (Li), chromium (Cr) and/or aluminum (Al), and mayinclude at least one reflective film having a relatively large thicknessand at least one transmissive film including transparent conductiveoxide such as indium tin oxide (ITO), indium zinc oxide (IZO), zincoxide (ZnO) and/or indium oxide (In₂O₃). In addition, the counterelectrode 170 may be formed of a metal such as magnesium (Mg), silver(Ag), gold (Au), calcium (Ca), lithium (Li), chromium (Cr) and/oraluminum (Al), and may include a transflective film having a relativelysmall thickness or a transmissive film may including transparentconductive oxide such as indium tin oxide (ITO), indium zinc oxide(IZO), zinc oxide (ZnO) and/or indium oxide (In₂O₃).

When the display device does not display an image, a user looking at thedisplay device from a top of the light emitting element EL in which thepixel electrode 150 is the reflective electrode and the counterelectrode 170 is the transmissive electrode may recognize the protrusionof the pixel electrode 150. However, in exemplary embodiments of thepresent invention, the second conductive line 130 is disposed in thegroove GR1 of the first insulating layer 120 that is recessed in thedirection towards the substrate 100, so that the thickness of the secondprotrusion of the pixel electrode 150 may be reduced. Accordingly, thevisibility of the display device mays he increased.

FIGS. 8, 9, 10, and 11 are cross-sectional views illustrating steps in amethod of manufacturing the display device of FIG. 7 according to anexemplary embodiment of the present invention.

Referring to FIG. 8, the first conductive line 110 may be formed on thesubstrate 100, and the first insulating layer 120 which at leastpartially covers the first conductive line 110 may be formed on thesubstrate 100.

A buffer layer 101, a gate insulating layer 103, a first interlayerinsulating layer 105, and a second interlayer insulating layer 107 maybe sequentially disposed on the substrate 100.

The first conductive line 110 may be formed on the second interlayerinsulating layer 107. For example, the first conductive layer may beformed by depositing a conductive material such as aluminum (Al),titanium (Ti) and/or copper (Cu) on the second interlayer insulatinglayer 107 by using physical vapor deposition. The physical vapordeposition may be performed by a process such as sputtering. The firstconductive line 110 may be formed by etching the first conductive layer.

Next, the first insulating layer 120 which at least partially covers thefirst conductive line 110 may be formed on the second interlayerinsulating layer 107. For example, the first insulating layer 120 may beformed by applying an organic insulating material such as a photoresistonto the second interlayer insulating layer 107 on which the firstconductive line 110 is formed. The formation of the first insulatinglayer 120 may be performed by using a process such as spin coating andthe like.

Referring to FIG. 9, the contact hole CH1 and the groove GR1 may beformed in the first insulating layer 120.

In an exemplary embodiment of the present invention, the contact holeCH1 and the groove GR1 may be formed by using a halftone mask HM. Thehalftone mask HM may include a light blocking part P1, lighttransmitting part P2, and a semi-light transmitting part P3. The lightblocking part P1 may block light, and the light transmitting part P2 maytransmit the light. The semi-light transmitting part P3 may block aportion of the light and transmit another portion of the light. Forexample, transmissivity of the semi-light transmitting part P3 may begreater than transmissivity of the light blocking part P1, and may beless than transmissivity of the light transmitting part P2.

First, the halftone mask HM may be disposed on the first insulatinglayer 120. The light transmitting part P2 may at least partially overlapan area in which the contact hole CH1 is formed, and the semi-lighttransmitting part P3 may at least partially overlap an area in which thegroove GR1 is formed. Next, the contact hole CH1 and the groove GR1 maybe formed at substantially the same time by exposing the firstinsulating layer 120 to light using the halftone mask HM, and developingthe first insulating layer 120 exposed to the light.

In an exemplary embodiment of the present invention, the groove GR1 maybe formed by isotropically etching the first insulating layer 120. Thefirst insulating layer 120 may be isotropically etched in a process ofdeveloping a portion of the first insulating layer 120 exposed to thelight by the semi-light transmitting part P3 of the halftone mask HM. Inthis case, the groove GR1 may have a round shape recessed in thedirection towards the substrate 100.

Referring to FIG. 10, the second conductive line 130 which fills thecontact hole CH1 may be formed in the groove GR1 on the first insulatinglayer 120. For example, the second conductive layer may be formed bydepositing a conductive material, such as aluminum (Al), titanium (Ti),and copper (Cu), on the first insulating layer 120 by using physicalvapor deposition such as sputtering, and the second conductive line 130may be formed by etching the second conductive layer.

The second conductive line 130 may be formed in the groove GR1 having around shape recessed in the direction towards the substrate 100.Accordingly, the second conductive line 130 may have a ‘U’ shape whenviewed in a cross-sectional view.

Referring to FIG. 11, the second insulating layer 140 which at leastpartially covers the second conductive line 130 may be formed on thefirst insulating layer 120. For example, the second insulating layer 140may he formed by applying an organic insulating material such aspolyimide (PI) onto the first insulating layer 120 on which the secondconductive line 130 is formed. The formation of the second insulatinglayer 140 may be performed by using a process such as spin coating andthe like.

In the present exemplary embodiment of the present invention, thecontact hole CH1 and the groove GR1 are formed in the first insulatinglayer 120 at substantially the same time by using the halftone mask HM,so that an additional process for forming the groove GR1 may be omitted.Accordingly, a manufacturing cost and a manufacturing time for producingthe display device may be reduced.

FIG. 12 is a cross-sectional view illustrating the display device takenalong line II-II′ of FIG. 1. according to an exemplary embodiment of thepresent invention. In the exemplary embodiment of the display device,which will be described with reference to FIG. 12, descriptions ofcomponents substantially identical to previously designated componentsof the display device described with reference to FIG. 7 will beomitted.

Referring to FIG. 12, the first conductive line 110 may be disposed onthe second interlayer insulating layer 107. A first insulating layer1120 which at least partially covers the first conductive line 110 maybe disposed on the second interlayer insulating layer 107.

In an exemplary embodiment of the present invention, the firstinsulating layer 1120 may include at least one of an organic insulatingmaterial and an inorganic insulating material. For example, the firstinsulating layer 1120 may include a photosensitive material, such as aphotoresist and/or silicon oxide, silicon nitride and/or siliconoxynitride.

The first insulating layer 1120 may have a contact hole CH2 and a grooveGR2. The contact hole CH2 may have a depth D21 corresponding to adistance from the top surface of the first conductive line 110 to a topsurface of the first insulating layer 1120.

The groove GR2 may be recessed in the direction towards the substrate100, and may have a depth D22 smaller than the depth D21 of the contacthole CH2. The top surface of the first insulating layer 1120 may berecessed in the direction towards the substrate 100 by the groove GR2when viewed in a cross-sectional view.

In an exemplary embodiment of the present invention, the groove GR2 mayhave a rectangular shape recessed in the direction towards the substrate100. For example, sides of the groove GR2 may be orthogonally connectedin a plan view and/or cross-sectional view. The depth D22 of the grooveGR2 may be substantially the same from a periphery to a central portionof the groove GR2. In this case, the depth D22 of the groove GR2 may besubstantially uniform.

A second conductive line 1130 may be disposed in the groove GR2 on thefirst insulating layer 1120. The second conductive line 1130 may beconnected to the first conductive line 110 through the contact hole CH2.

The second conductive line 1130 may have a flat top surface. The secondconductive line 1130 may be disposed in the groove GR2 on the firstinsulating layer 1120, and the top surface of the second conductive line1130 may be formed along a profile of the groove GR2. Accordingly, thesecond conductive line 1130 may have the flat top surface extendingalong the profile of the groove GR2, which has a rectangular shaperecessed in the direction towards the substrate 100.

In an exemplary embodiment of the present invention, the depth D22 ofthe groove GR may be substantially equal to a thickness of the secondconductive line 1130. In this case, a height of the top surface of thesecond conductive line 1130 may be substantially equal to a height ofthe top surface of the first insulating layer 1120 (e.g., coplanartherewith).

A second insulating layer 1140 which at least partially covers thesecond conductive line 1130 may be disposed on the first insulatinglayer 1120. The second insulating layer 1140 may include an organicinsulating material.

A top surface of the second insulating layer 1140 may be formed alongprofiles of the top surfaces of the first insulating layer 1120 and thesecond conductive line 1130 which are disposed under the secondinsulating layer 1140. The second conductive line 1130 is disposed inthe groove GR2 of the first insulating layer 1120 that is recessed inthe direction towards the substrate 100, and the thickness of the secondconductive line 1130 is substantially equal to the depth D22 of thegroove GR2, so that a protrusion may not be formed on the top surface ofthe second insulating layer 1140. For example, the second insulatinglayer 1140 may have a flat top surface.

A pixel electrode 1150 may be disposed on the second insulating layer1140. The pixel electrode 1150 may at least partially overlap the secondconductive line 1130.

A top surface of the pixel electrode 1150 may be formed along a profileof the top surface of the second insulating layer 1140 which is disposedunder the pixel electrode 1150. For example, an upper and lower surfaceof the pixel electrode 1150 and an upper surface of the secondinsulating layer 1140 may be parallel and coplanar. The secondinsulating layer 1140 has the flat top surface, so that a protrusion maynot be formed on the top surface of the pixel electrode 1150.

FIGS. 13, 14, 15, 16, and 17 are cross-sectional views illustratingsteps in a method manufacturing the display device of FIG. 12. In themethod of manufacturing the display device, which will be described withto FIGS. 13 to 17, descriptions of components substantially identical tothe components of the method of manufacturing the display devicepreviously described with reference to FIGS. 8 to 11 will be omitted.

Referring to FIG. 13, the first conductive line 110 may be formed on thesubstrate 100, and the first insulating layer 1120 which at leastpartially covers the first conductive line 110 may be formed on thesubstrate 100.

The first conductive line 110 may be formed on the second interlayerlayer 107.

Next, the first insulating layer 1120 which at least partially coversthe first conductive line 110 may be formed on the second interlayerinsulating layer 107. In an exemplary embodiment of the presentinvention in which the first insulating layer 1120 includes an organicinsulating material, the first insulating layer 1120 may be formed byapplying an organic insulating material such as a photoresist onto thesecond interlayer insulating layer 107 on which the first conductiveline 110 is formed. The formation of the first insulating layer 1120 maybe performed by a process such as spin coating. In an exemplaryembodiment of the present invention which the first insulating layer1120 includes an inorganic insulating material, the first insulatinglayer 1120 may be formed by depositing an inorganic insulating materialsuch as silicon oxide, silicon nitride and/or silicon oxynitride on thesecond interlayer insulating layer 107 on which the first conductiveline 110 is formed. The first insulating layer 1120 may be formed byusing a chemical vapor deposition process such as PECVD.

Referring to FIG. 14, the contact hole CH2 may be formed in the firstinsulating layer 1120. The contact hole CH2 may expose the firstconductive line 110.

In an exemplary embodiment of the present invention, the contact holeCH2 may be formed by using a first mask M1. The first mask M1 mayinclude a light blocking part P1 and a light transmitting part P2. Thelight blocking part P1 may block light, and the light transmitting partP2 may transmit the light.

In an exemplary embodiment of the present invention in which the firstinsulating layer 1120 includes an organic insulating material, the firstmask M1 may be disposed on the first insulating layer 1120. The lighttransmitting part P2 may at least partially overlap an area in which thecontact hole CH2 is formed. Next, the contact hole CH2 may be formed byexposing the first insulating layer 1120 to light by using the firstmask M1, and developing the first insulating layer 1120 exposed to thelight.

In an exemplary embodiment of the present invention in which the firstinsulating layer 1120 includes an inorganic insulating material, a firstphotoresist layer may be formed on the first insulating layer 1120.Next, the first mask M1 may be disposed on the first photoresist layer.The light transmitting part P2 may at least partially overlap an area inwhich the contact hole CH2 is formed. Thereafter, a first photoresistpattern may be formed by exposing the first photoresist layer to lightby using the first mask M1, and developing the first photoresist layerexposed to the light. Then, the contact hole CH2 may be formed byetching the first insulating layer 1120 using the first photoresistpattern as an etching mask. Next, the first photoresist pattern may bestripped.

Referring to FIG. 15, the groove GR2 may be formed in the firstinsulating layer 1120. The groove GR2 may be recessed in the directiontowards the substrate 100, and may have the depth D22 smaller than thedepth D21 of the contact hole CH2.

In an exemplary embodiment of the present invention, the groove GR2 maybe formed by using a second mask M2. The second mask M2 may include alight blocking part P1 and a light transmitting part P2. The lightblocking part P1 may block light, and the light transmitting part P2 maytransmit the light.

First, a second photoresist layer may be formed on the first insulatinglayer 1120. Next, the second mask M2 may be disposed on the secondphotoresist layer. The light transmitting part P2 may at least partiallyoverlap an area in which the groove GR2 is formed. Thereafter, a secondphotoresist pattern may be formed by exposing the second photoresistlayer to light by using the second mask M2, and developing the secondphotoresist layer exposed to the light. Then, the groove GR2 may beformed by etching the first insulating layer 1120 by using the secondphotoresist pattern as an etching mask. Next, the second photoresistpattern may be stripped.

In an exemplary embodiment of the present invention, the groove GR2 maybe formed by anisotropically etching the first insulating layer 1120.For example, the insulating layer 1120 may be an isotropically etched ina process of etching the first insulating layer 1120 exposed by thesecond photoresist pattern through a dry etching scheme. In this case,the groove GR2 may have a rectangular shape recessed in the directiontowards the substrate 100.

Referring to FIG. 16, the second conductive line 1130 which fills thecontact hole CH2 may be formed in the groove GR2 on the first insulatinglayer 1120.

The second conductive line 1130 may be formed in the groove GR2 having arectangular shape recessed in the direction towards the substrate 100.Accordingly, the second conductive line 1130 may have the flat topsurface.

Referring to FIG. 17, the second insulating layer 1140 which at leastpartially covers the second conductive line 1130 may be formed on thefirst insulating layer 1120.

In the present exemplary embodiment of the present invention, the firstinsulating layer 1120 is anisotropically etched by using the second maskM2 to form the groove GR2 having a rectangular shape recessed in thedirection towards the substrate 100, so that the second conductive line1130 having the flat top surface may be formed. Accordingly, the secondinsulating layer 1140 having the flat top surface may be formed, and thevisibility of the display device may be increased.

The display device according to the exemplary embodiments of the presentinvention may be applied to a display device included in a computer, anotebook, a mobile phone, a smartphone, a smart pad, a PMP, a PDA, MP3player, or the like.

While exemplary embodiments of the present invention have beenparticularly shown and described above, it will be understood thatvarious changes in form and details may be made therein withoutdeparting from the spirit and scope of the present invention.

1. A display device, comprising: a first conductive line disposed on a substrate; a first insulating layer disposed on the substrate at least partially covering the first conductive line, the first insulating layer having a contact hole, which exposes the first conductive line, and a groove recessed in a direction towards the substrate, the groove having a depth smaller than a depth of the contact hole; and a second conductive line disposed in the groove on the first insulating layer and connected to the first conductive line through the contact hole.
 2. The display device of claim 1, further comprising a second insulating layer disposed on the first insulating layer at least partially covering the second conductive line, wherein the groove has a round shape recessed in the direction towards the substrate.
 3. The display device of claim 2, wherein the second conductive line has a ‘U’ shape.
 4. The display device of claim 1, wherein the groove has a rectangular shape recessed in the direction towards the substrate.
 5. The display device of claim 4, wherein the second conductive line has a flat top surface.
 6. The display device of claim 1, wherein a maximum depth of the groove is substantially equal to a thickness of the second conductive line.
 7. The display device of claim 1, wherein the first conductive line extends in a first direction and is configured to transmit a data signal.
 8. The display device of claim 7, wherein the second conductive line extends in the first direction and a second direction intersecting the first direction, and wherein the second conductive line connects a pad to the first conductive line.
 9. The display device of claim 1, wherein the first insulating layer includes an organic insulating material and an inorganic insulating material.
 10. The display device of claim 2, wherein the second insulating layer includes an organic insulating material.
 11. The display device of claim 2, further comprising: a pixel electrode disposed on the second insulating layer at least partially overlapping the second conductive line; a light emitting layer disposed on the pixel electrode; and a counter electrode disposed on the light emitting layer.
 12. The display device of claim 11, wherein the pixel electrode is a reflective electrode, and wherein the counter electrode is a transmissive electrode.
 13. A method of manufacturing a display device, comprising: forming a first conductive line on a substrate; forming a first insulating layer at least partially covering the first conductive line; forming a contact hole exposing the first conductive line in the first insulating layer by using a halftone mask; forming a groove in the first insulating layer by using the halftone mask, the groove is recessed in a direction towards the substrate and has a depth smaller than a depth of the contact hole; and forming a second conductive line at least partially filling the contact hole and the groove.
 14. The method of claim 13, further comprising forming a second insulating layer at least partially covering the second conductive line, wherein the first insulating layer includes an organic insulating material.
 15. The method of claim 13, wherein the groove is formed by isotropically etching the first insulating layer.
 16. The method of claim 13, wherein the groove has a round shape recessed in the direction towards the substrate.
 17. A method of manufacturing a display device, the method comprising: forming a first conductive line on a substrate; forming a first insulating layer at least partially covering the first conductive line; forming a contact hole exposing the first conductive line in the first insulating layer by using a first mask; forming a groove in the first insulating layer by using a second mask, the groove is recessed in a direction towards the substrate and has a depth smaller than a depth of the contact hole; forming a second conductive line at least partially filling the contact hole and the groove; and forming a second insulating layer at least partially covering the second conductive line.
 18. The method of claim 17, wherein the first insulating layer includes an organic insulating material and an inorganic insulating material.
 19. The method of claim 17, wherein the groove is formed by anisotropically etching the first insulating layer.
 20. The method of claim 17, wherein the groove has a rectangular shape recessed in the direction towards the substrate. 